Service Restoration Of Active Distribution Network

Active distribution network (ADN) refers to distribution network having the ability of combinable controlling various distributed energy resources, and effectively connects generation with consumers’ need through active controlling and management. The volatile and strong intermittent of renewable energy limit the operation of DG’s connecting to grid, which is needed to be coordinated and controlled. ADN has the ability of strengthening the accessibility of distribution network to the renewable, increasing the quantity of DG interconnection and operation efficiency, improving power quality and reliability, optimizing asset utilization, and delaying expansion investment of distribution network. The traditional distribution network service restoration can not meet the request of DG’s connection on a large scale, which is faced with huge challenges.As service restoration strategy is proposed based on the characteristics of the ADN and effects of DG access, ADN is a multi-objective, multi-constraint, and complex optimal problem. DG’s interconnection, island operation with the around load when DG can work as back-up source and quit operation when DG cannot work as back-up source. Model of DG is established based on characteristics of DG. Considering the users’ prior level, the load amounts restored, the counts of switch operation, the network loss after the power restoration, and the operation of power sources, this article establishes a restoration model based on grid actual situation, which is more realistic for the ADN. As a different dimension of different objective, this article proposes the generalized model in order to compare those solutions conveniently.The topology of distribution network is introduced, and connecting the structural characteristics of distribution network, through the connecting relationship of each node and branch, the breadth-first search method is adopted and it can dynamically recognize the network structure’s changing. Combining with the characteristics of distribution network topological structure, Newton-Raphson method is adopted based on comparative to several power flow methods. After that, the paper uses genetic algorithm to get recovery scheme.MATLAB is used to realize topology identification of the distribution network, removing the infeasible solution, calculating for power flow of distribution network, and restoration schemes.This article takes the IEEE standard33nodes and33nodes containing DG, IEEE69standard69nodes, and another establish mathematical model containing DG as examples to demonstrate the validity and reliability.